/* This file defines an XML parser, with a few kludges to make it
 * useable for HTML. autoSelfClosers defines a set of tag names that
 * are expected to not have a closing tag, and doNotIndent specifies
 * the tags inside of which no indentation should happen (see Config
 * object). These can be disabled by passing the editor an object like
 * {useHTMLKludges: false} as parserConfig option.
 */

var XMLParser = Editor.Parser = (function() {
  var Kludges = {
	autoSelfClosers: {"br": true, "img": true, "hr": true, "link": true, "input": true,
					  "meta": true, "col": true, "frame": true, "base": true, "area": true},
	doNotIndent: {"pre": true, "!cdata": true}
  };
  var NoKludges = {autoSelfClosers: {}, doNotIndent: {"!cdata": true}};
  var UseKludges = Kludges;
  var alignCDATA = false;

  // Simple stateful tokenizer for XML documents. Returns a
  // MochiKit-style iterator, with a state property that contains a
  // function encapsulating the current state. See tokenize.js.
  var tokenizeXML = (function() {
	function inText(source, setState) {
	  var ch = source.next();
	  if (ch == "<") {
		if (source.equals("!")) {
		  source.next();
		  if (source.equals("[")) {
			if (source.lookAhead("[CDATA[", true)) {
			  setState(inBlock("xml-cdata", "]]>"));
			  return null;
			}
			else {
			  return "xml-text";
			}
		  }
		  else if (source.lookAhead("--", true)) {
			setState(inBlock("xml-comment", "-->"));
			return null;
		  }
		  else {
			return "xml-text";
		  }
		}
		else if (source.equals("?")) {
		  source.next();
		  source.nextWhile(matcher(/[\w\._\-]/));
		  setState(inBlock("xml-processing", "?>"));
		  return "xml-processing";
		}
		else {
		  if (source.equals("/")) source.next();
		  setState(inTag);
		  return "xml-punctuation";
		}
	  }
	  else if (ch == "&") {
		while (!source.endOfLine()) {
		  if (source.next() == ";")
			break;
		}
		return "xml-entity";
	  }
	  else {
		source.nextWhile(matcher(/[^&<\n]/));
		return "xml-text";
	  }
	}

	function inTag(source, setState) {
	  var ch = source.next();
	  if (ch == ">") {
		setState(inText);
		return "xml-punctuation";
	  }
	  else if (/[?\/]/.test(ch) && source.equals(">")) {
		source.next();
		setState(inText);
		return "xml-punctuation";
	  }
	  else if (ch == "=") {
		return "xml-punctuation";
	  }
	  else if (/[\'\"]/.test(ch)) {
		setState(inAttribute(ch));
		return null;
	  }
	  else {
		source.nextWhile(matcher(/[^\s\u00a0=<>\"\'\/?]/));
		return "xml-name";
	  }
	}

	function inAttribute(quote) {
	  return function(source, setState) {
		while (!source.endOfLine()) {
		  if (source.next() == quote) {
			setState(inTag);
			break;
		  }
		}
		return "xml-attribute";
	  };
	}

	function inBlock(style, terminator) {
	  return function(source, setState) {
		while (!source.endOfLine()) {
		  if (source.lookAhead(terminator, true)) {
			setState(inText);
			break;
		  }
		  source.next();
		}
		return style;
	  };
	}

	return function(source, startState) {
	  return tokenizer(source, startState || inText);
	};
  })();

  // The parser. The structure of this function largely follows that of
  // parseJavaScript in parsejavascript.js (there is actually a bit more
  // shared code than I'd like), but it is quite a bit simpler.
  function parseXML(source) {
	var tokens = tokenizeXML(source);
	var cc = [base];
	var tokenNr = 0, indented = 0;
	var currentTag = null, context = null;
	var consume, marked;

	function push(fs) {
	  for (var i = fs.length - 1; i >= 0; i--)
		cc.push(fs[i]);
	}
	function cont() {
	  push(arguments);
	  consume = true;
	}
	function pass() {
	  push(arguments);
	  consume = false;
	}

	function mark(style) {
	  marked = style;
	}
	function expect(text) {
	  return function(style, content) {
		if (content == text) cont();
		else mark("xml-error") || cont(arguments.callee);
	  };
	}

	function pushContext(tagname, startOfLine) {
	  var noIndent = UseKludges.doNotIndent.hasOwnProperty(tagname) || (context && context.noIndent);
	  context = {prev: context, name: tagname, indent: indented, startOfLine: startOfLine, noIndent: noIndent};
	}
	function popContext() {
	  context = context.prev;
	}
	function computeIndentation(baseContext) {
	  return function(nextChars, current) {
		var context = baseContext;
		if (context && context.noIndent)
		  return current;
		if (alignCDATA && /<!\[CDATA\[/.test(nextChars))
		  return 0;
		if (context && /^<\//.test(nextChars))
		  context = context.prev;
		while (context && !context.startOfLine)
		  context = context.prev;
		if (context)
		  return context.indent + indentUnit;
		else
		  return 0;
	  };
	}

	function base() {
	  return pass(element, base);
	}
	var harmlessTokens = {"xml-text": true, "xml-entity": true, "xml-comment": true, "xml-processing": true};
	function element(style, content) {
	  if (content == "<") cont(tagname, attributes, endtag(tokenNr == 1));
	  else if (content == "</") cont(closetagname, expect(">"));
	  else if (style == "xml-cdata") {
		if (!context || context.name != "!cdata") pushContext("!cdata");
		if (/\]\]>$/.test(content)) popContext();
		cont();
	  }
	  else if (harmlessTokens.hasOwnProperty(style)) cont();
	  else mark("xml-error") || cont();
	}
	function tagname(style, content) {
	  if (style == "xml-name") {
		currentTag = content.toLowerCase();
		mark("xml-tagname");
		cont();
	  }
	  else {
		currentTag = null;
		pass();
	  }
	}
	function closetagname(style, content) {
	  if (style == "xml-name" && context && content.toLowerCase() == context.name) {
		popContext();
		mark("xml-tagname");
	  }
	  else {
		mark("xml-error");
	  }
	  cont();
	}
	function endtag(startOfLine) {
	  return function(style, content) {
		if (content == "/>" || (content == ">" && UseKludges.autoSelfClosers.hasOwnProperty(currentTag))) cont();
		else if (content == ">") pushContext(currentTag, startOfLine) || cont();
		else mark("xml-error") || cont(arguments.callee);
	  };
	}
	function attributes(style) {
	  if (style == "xml-name") mark("xml-attname") || cont(attribute, attributes);
	  else pass();
	}
	function attribute(style, content) {
	  if (content == "=") cont(value);
	  else if (content == ">" || content == "/>") pass(endtag);
	  else pass();
	}
	function value(style) {
	  if (style == "xml-attribute") cont(value);
	  else pass();
	}

	return {
	  indentation: function() {return indented;},

	  next: function(){
		var token = tokens.next();
		if (token.style == "whitespace" && tokenNr == 0)
		  indented = token.value.length;
		else
		  tokenNr++;
		if (token.content == "\n") {
		  indented = tokenNr = 0;
		  token.indentation = computeIndentation(context);
		}

		if (token.style == "whitespace" || token.type == "xml-comment")
		  return token;

		while(true){
		  consume = marked = false;
		  cc.pop()(token.style, token.content);
		  if (consume){
			if (marked)
			  token.style = marked;
			return token;
		  }
		}
	  },

	  copy: function(){
		var _cc = cc.concat([]), _tokenState = tokens.state, _context = context;
		var parser = this;

		return function(input){
		  cc = _cc.concat([]);
		  tokenNr = indented = 0;
		  context = _context;
		  tokens = tokenizeXML(input, _tokenState);
		  return parser;
		};
	  }
	};
  }

  return {
	make: parseXML,
	electricChars: "/",
	configure: function(config) {
	  if (config.useHTMLKludges != null)
		UseKludges = config.useHTMLKludges ? Kludges : NoKludges;
	  if (config.alignCDATA)
		alignCDATA = config.alignCDATA;
	}
  };
})();
